pax_tar

Simple C++ Tar API using PAX Extended Header. Create & Read Tars supporting large file sizes and path names. Currently doesn't support directories or symlinks but could easily be added if needed.

Inspiration and some code taken from https://github.com/rxi/microtar.

I wanted support for 64 bit file sizes under Windows as well as files > 8gb in the archive. I originally modified microtar to add Pax Extended Headers but decided it would corrupt the projects simplicity.

Supported Environments & Build Systems

Prerequisites

We use the excellent fmtlib: https://github.com/fmtlib/fmt.

Windows: automatic dependency in VCPKG
Linux: clone from github, checkout 5.1.0, build and install with cmake

Windows 10 x64 VCPKG

As this is not a fully complete TAR library I have not submitted it to the VCPKG curated list. However, I have written the port file so you can still easily install with VCPKG.

Clone https://github.com/researcher2/pax_tar_vcpkg_port.git into "vcpkg/ports/pax-tar"

vcpkg install pax-tar:x64-windows

Windows 10 x64 Visual Studio

Visual Studio 2017 Solution included for self building:

Static CRT lib
Dynamic CRT lib
Test Project
Examples Project (can be used to test vcpkg dynamic crt linkage)
Testing vcpkg static crt linkage project

Linux (Tested Under CentOS)

We use meson: https://mesonbuild.com/index.html

Note that the final install step assumes you want to install into the system directories and you have meson installed by sudo user already.

git clone https://github.com/researcher2/pax_tar.git
cd pax_tar
mkdir build
cd build
meson ..
ninja
sudo ninja install

Basic Usage

The below code is also available in "pax_tar_examples.cpp".

#include <pax_tar.h> // Will resolve to VCPKG or system path

#include <iostream>
using std::cout; using std::endl;

#include <experimental/filesystem>
namespace fs = std::experimental::filesystem;

void paxWriting(string &testFileName);
void paxReading(string &testFileName);

int main()
{
    string testFileName = "test.tar";
    if (fs::exists(testFileName))
        fs::remove(testFileName);
    
    paxWriting(testFileName);
    paxReading(testFileName);

    getchar();
}

void paxWriting(string &testFileName)
{
    string data1 = "Hello world";
    string data2 = "Goodbye world";
    string data3 = "Guess who's back?";

    string path1 = "test1.txt";
    string path2 = "test2.txt";
    string path3 = "test3.txt";

    TarFile tarFile(testFileName);

    tarFile.addFile(path1, data1.size());
    tarFile.writeData((char*)data1.data(), data1.size());
    tarFile.finaliseFile();

    tarFile.addFile(path2, data2.size());
    tarFile.writeData((char*)data2.data(), data2.size());
    tarFile.finaliseFile();

    tarFile.addFile(path3, data3.size());
    tarFile.writeData((char*)data3.data(), data3.size());
    tarFile.finaliseFile();
}

void paxReading(string &testFileName)
{
    TarFile tarFile(testFileName);

    // Iterate through all files
    for (TarFileEntry &fileEntry : tarFile.files)
    {
        string loadedData;
        tarFile.getFileData(fileEntry, loadedData);

        cout << "Path: " << fileEntry.path << " ";
        cout << "Size: " << fileEntry.size << " ";
        cout << "Data: " << loadedData << endl;
    }

    // Find functionality:
    if (tarFile.filesByPath.count("test1.txt"))
    {
        TarFileEntry &fileEntry = *tarFile.filesByPath["test1.txt"];
        string loadedData;
        tarFile.getFileData(fileEntry, loadedData);

        cout << "Path: " << fileEntry.path << " ";
        cout << "Size: " << fileEntry.size << " ";
        cout << "Data: " << loadedData << endl;
    }
}

researcher2 / pax_tar